The color image-forming method most generally used in a silver halide color photographic light-sensitive material includes a method in which an aromatic primary amine series color developing agent oxidized with exposed silver halide as an oxidizing agent is reacted with a coupler to form indophenol, indo-aniline, indamine, azomethine, phenoxazine, phenazine, and the dyes equivalent thereto. In such a system, a method in which a color image is reproduced by a subtractive color process is used, and generally the amounts of the three color dyes formed of yellow, magenta and cyan are changed to form the color image.
A phenol series or naphthol series cyan coupler is generally used for forming a cyan dye image. However, these couplers have a problem in that since they have an unfavorable absorption in the green light region and the blue light region, they markedly deteriorate particularly the color reproduction performance of blue and green colors, and therefore it is strongly desired to solve this problem.
The 2,4-diphenylimidazole series cyan couplers described in European Patent 0,249,453A2 have been proposed as a means for solving this problem. In the dyes formed from these couplers, the absorptions in the green and blue regions are reduced as compared with a conventional dye and they are certainly preferable in terms of color reproduction. However, the color reproduction performance can not be regarded sufficient even with these couplers and further improvement is desired. Further, there are other serious problems with these couplers. Their reactivity with the oxidation product of a developing agent, that is, their coupling activity, is low. Also, the dyes formed have a notably low fastness to heat and light. Therefore these couplers are not suited for practical use.
Further, in the pyrazoloazole series cyan couplers described in JP-A-64-552 (the term "JP-A" as used herein means an unexamined published Japanese patent application), JP-A-64-553, JP-A-64-554, JP-A-64-555, JP-A-64-556, and JP-A-64-557, the unfavorable absorptions in the green and blue regions are reduced as compared with the conventional dyes but the color reproduction performance is not sufficient as well and the problem that their color developing performance is markedly low still remains.
Further, the pyrrolopyrazole series cyan couplers are disclosed in European Patent 0,456,226A1 as a coupler providing an excellent hue. These couplers are improved in terms of their color reproduction performance as compared with the above couplers but they are not yet sufficient and have the defect that the color fog is large in the unexposed areas. In addition, their color developing performance has not yet reached a sufficiently satisfactory level.
The pyrrolotriazole series cyan couplers having a specific substituent described in European Patents 0,491,197 and 0,488,248 have been found out as the cyan coupler which reconciles the above subjects in the cyan coupler, that is, a good color developing performance and less unfavorable absorptions in the green and blue regions. These cyan couplers form a dye having an excellent absorption characteristic, that is, a dye having a large molar absorption coefficient and a sharp spectral band width in a short wavelength (the unfavorable absorptions in the green and blue regions are reduced) and have a high reactivity with a developing agent oxidation product. In addition, the dyes formed therefrom have an excellent fastness to light and heat and therefore they are preferred.
Meanwhile, in a conventional color photographic paper, a polyolefin layer containing titanium oxide kneaded and dispersed therein is provided on the surface of the emulsion-coated side of a substrate in order to increase the light reflection efficiency as well as the waterproof performance. In this case, while titanium oxide raises the image quality by increasing particularly the whiteness degree of the photographic paper, it tends to deteriorate the flatness and the glossiness of the photographic paper surface.
European Patent 0,507,489 discloses a support on which a composition comprising a resin containing polyester as a main component and a white pigment is coated at least on the surface of the emulsion-coated side. The whiteness degree can be raised by this technique without deteriorating the smoothness and the glossiness on the surface of a photographic paper.